1. Field of the Invention
The present invention relates to landscape water conservation by automating the water budget feature of irrigation controllers, that have heretofore been manually set.
The present invention relates to the management and conservation of irrigation water, primarily for, but not limited to, residential, commercial, and municipal landscaping applications. More specifically, numerous automated methods and apparatus are provided for adjusting irrigation schedule intervals or station run times using simplified water budgeting methods that use pre-determined periodic environmental water budgeting percentage data (compiled into bell shaped water budget percentage curves) based upon the time of year, location, or both. The pre-determined water budgeting percentage data may be used independently or with current environmental data and/or local watering restrictions, and/or with one or more environmental sensors, and then used to adjust irrigation run times, watering intervals, watering days, or watering times of the day to conserve landscape water. Physical embodiments may be provided within controllers, as add-ons or plug-ins, or with central irrigation systems to provide automation of water budgeting, a common manual feature of most landscape irrigation controllers.
2. Description of the Prior Art
Many regions of the United States lack sufficient water resources to satisfy all of their competing agricultural, urban, commercial and environmental needs. The “California Water Plan Update” published in 2009 by the California Department of Water Resources indicates that 80 million acre feet (maf) of water is needed to satisfy the annual water needs of the State of California. Of this amount, approximately forty-six percent is required for environmental purposes, forty-three percent for agricultural purposes, and eleven percent (approximately 8.8 maf) for urban use. Of this urban amount, 70% is for residential use, of which 50% is for landscaping.
The California Department of Water Resources, the EPA, and the Irrigation Association (IA) among others, have encouraged landscape water conservation with the use of “Smart” water technology with smart irrigation controllers, rain sensors, and soil moisture sensors. A smart controller is generally defined as one that can adjust its irrigation schedule daily based upon current weather or environmental conditions. Performance standards have been set to determine the level of efficiency for each of these products with Smart Water Application Technology (SWAT) testing conducted at the Center for Irrigation Technology in Fresno, Calif. Twenty irrigation controllers have undergone this testing to date with results posted on the IA web site. To date, all but three of the successfully tested controllers have been evapotranspiration (ET) based. The three non ET tested products use temperature budgeting, this inventor's technology presented in presented in parent pending application Ser. No. 11/879,700, grand parent U.S. Pat. No. 7,266,428, great grandparent U.S. Pat. No. 7,058,478, and provisional application 60/465,457 filed on Apr. 25, 2003. These results can be noted in FIGS. 9A, 9B, and 9C.
To further encourage the use of smart controllers, many water districts are offering rebates for those controllers that are posted in the IA web site with SWAT results. Soil moisture sensors and rain switches are the next set of smart devices that will be SWAT tested and posted. Controller add-ons and plug-ins have also recently started to be SWAT tested, such as the Hunter Solar Sync, the Irritrol Climate Logic, and this inventor's Universal Smart Module (see FIG. 9C). A distinction is made between an add-on or plug-in. Both are devices outside an irrigation controller and designed to make existing conventional (non smart) controllers smart. However, an add-on is typically mounted on the output of an irrigation controller and usually breaks the common line to control irrigation. As such, an add-on can normally make any existing controller smart. A plug-in provides data directly to the irrigation controller microprocessor and must normally be compatible with a certain brand or model controller.
As stated in this applicant's previous applications, ET based controllers, add-ons and plug-ins, while theoretically effective, were projected to be far too complicated or expensive or required monthly service fees to be an effective practical means for meaningful water conservation. Since 2003, this fact has not changed. The industry is still searching for products that provide real water conservation rather than theoretical water conservation. After seven years, still far fewer than 1% of irrigation controllers installed are smart, and many of them were installed only because they were provided free of charge or highly rebated. Furthermore, studies have shown that within one year of installation, less than half of those ET based smart controllers are still being used in their Smart mode. This fact was underscored by the AquaCraft study of weather based irrigation controllers (WBIC) sponsored by the California Department of Water Resources in 2009 that showed that the 3112 ET based smart controllers installed throughout California, only a 6% average water saving was recorded. Manufacturers had boasted that based on ET theory, 30-40% water savings would be possible.
At least fifteen different ET equations have been developed over the last fifty years. In FIG. 8, described in detail below, Cattaneo and Upham show four of those ET based data which indicate that the Pennman-Monteith data which is the standard used by the IA, DWR, and the FAO (food and agriculture office), is at certain times of the year as much as sixty percent different than the other three equations which all use the same CIMIS data.
The California Energy Commission was formed to provide recommendations to DWR for the implementation of California Assembly Bill 1881 concerning limiting the sale of smart controllers in California after January 2012. Due to the poor performance of ET based controllers, the Commission has suspended its meetings, leaving the implementation of bill 1881 in doubt. The reasons for its suspension are disagreement within the industry, disappointment of ET based controller performance, very poor sales of smart controllers in spite of rebates, and the state of California's economy.
All of these indicate that still after nearly a decade of ET and four decades of promoting soil moisture sensors, there is no clear consensus in the industry and government agencies as was originally predicted in this inventor's '478 patent.
In addition to the need for water conservation, many urban areas do not have the infrastructure necessary to serve their communities, which include pumping, delivery, and water pressure issues. As a consequence, many water districts have implemented restricted watering schedules to stabilize water deliveries and save water. These restrictions normally require periodic manual changes to irrigation schedules for compliance. An automated way to insure compliance would also be beneficial for both water conservation and infrastructure relief. Ideally, both smart technology and automated water restrictions could be incorporated within an irrigation controller or add-on or plug-in device to offer a choice to the water district depending upon their local conditions and needs. This subject referred to as “Time of Use” was explained by pending application Ser. No. 11/879,700 which is incorporated in its entirety herein. The present invention provides embodiments addressing both needs.
The present invention nor its predecessors do not state that ET and soil moisture based methods are not possible ways to help conserve water, but as currently embodied in other controllers (see Bureau of Reclamation report referenced herein), controllers and currently available ET methods are difficult to understand and implement. A number of references, patents, and published applications are in existence that cover ET-based methods and apparatus.
At the Feb. 17, 2004, EPA-sponsored “Water Efficient Product Market Enhancement Program” in Phoenix, Ariz., for landscaping irrigation systems and controllers, it was projected that thirty-six states will have severe water shortages by the year 2010. This projected shortage has proven to be relatively accurate as of the date of this application. A significant portion of this projected shortage was attributed to user neglect and system inefficiency in landscape irrigation. The California Urban Water Conservation Council estimated that the average California household utilized one-half acre foot of water (162,500 gallons) annually, and that fifty-five percent (89,375 gallons) of this amount was used for landscape irrigation. It further estimated that approximately one-third of the irrigation water was wasted, either due to inefficient irrigation systems or inadequate controller programming, oftentimes due in part to complicated controller programming procedures required of the operator. This results in a total annual waste of 1.81 maf of water for California households alone. Excessive water usages in municipal and commercial areas, golf courses and schools further contribute to the water shortage.
Such water shortages have forced many municipalities to enact strict water conservation measures. Two such measures include strongly encouraging the use of irrigation controllers that can adjust themselves to changing weather conditions, or instituting limitations of allowed watering days, or watering times during the day (sometimes referred to as Time-Of Use or “TOU” restrictions) both to minimize evaporation and during peak demand, which may vary during the various seasons. Some communities have also required the installation of water meters and “water police” auditors to enforce those schedules. Commercial and environmental users have enacted similar measures. For its part, the agricultural industry has responded to this shortage by resorting to drip, micro, and other low volume irrigation systems. However, after at least six years, there is still no consensus among consumers, water agencies, manufacturers, or state or federal government entities as to the most effective water conservation method or automated controls. For example, the California Energy Commission has suspended its proceedings for recommending labeling and sales standards; the California Department of Water Resources is not prepared to make recommendations concerning implementation of California Assembly Bill 1881 which would have required all irrigation controllers sold in California by January 2012 to be “smart.”
Virtually all current weather based irrigation controllers and systems still utilize meteorological data to estimate the evapotranspiration, or ET, for a particular location. ET is generally used to determine the landscape watering needs by requiring input data consisting of crop coefficient factors, soil type, precipitation rates, degree of shade, and slope. This information is generally used to determine the initial controller irrigation schedule. In some applications, daily or periodic ET based calculations convert (typically) daily ET data to adjusted station run times or watering schedules. Some of these ET types of controllers and add-on modules are manufactured by Weathermatic, Rain Master, ET Water Systems, Hydro Point, Rain Bird, Hunter, Irritrol, and Toro, among others. All smart controllers, devices, and soil moisture sensors currently available are reviewed by the U.S. Department of the Interior, Bureau of Reclamation, Lower Colorado Region, available from the Southern California Area Office, in their updated September 2009 “Weather and Soil Moisture Based Landscape Irrigation Scheduling Devices”.
The use and efficiency factors of ET based smart controllers is still in doubt. A recent large study of 3112 ET based controllers installed throughout California conducted by AquaCraft revealed a disappointing 6% water savings. In addition, much fewer than 1% conversion to smart controllers has been accomplished after seven years throughout the U.S., and of those, about half were either not programmed correctly due to ET complexity, or not used in their smart mode within the first year of installation, partially due to monthly ET data service fees. Furthermore, there is significant disagreement with regard to the EPA's WaterSense labeling proposals by the Irrigation industry. Finally, the EPA estimated in a document accompanying its WaterSense labeling first draft specification in December 2009 that the return on investment (ROI) for using an ET based controller was 15 years-a very long ROI which does not encourage conversion.
These continuing uncertainties and inefficiencies, along with cost, complexity, and the current state of the economy (which has deteriorated significantly since 2006) continue to slow efforts to convert to smart controller technology. Therefore, the industry is still seeking a simpler, more cost and a real water conservation effective solution. No matter how much water is theoretically saved by ET systems, the reality is that very little real water savings has been recorded to date using the currently available ET based and soil moisture sensing methods, even after the past six years of public education and municipal rebates. It is better to save real water than hypothetically saved water presented by most currently available ET based theories and methods which have been dominant to date.
Other than system inefficiencies, the main reason for landscape water waste was revealed in a marketing study conducted by the Irrigation Association (IA) and presented at the 2003 IA “Smart Water Application Technology” conference in San Diego, Calif. The study indicated that most consumers typically adjust their irrigation schedule only an average of three times a year, rather than on a daily or weekly basis, regardless of changes in environmental conditions. The relatively high cost of labor in many municipalities further prohibits frequent manual adjustments of irrigation controllers in the commercial and municipal markets. This generally results in over-irrigation and runoff, particularly during the off-seasons, oftentimes by as much as one to two hundred percent.
As an alternative to ET, soil moisture sensing devices and other methods of water conservation have been available for decades, but have enjoyed only limited success. Such devices and methods generally call for inserting moisture sensors into the soil to measure the soil moisture content. Newer soil moisture sensing technologies have more recently been developed, and claim to be theoretically accurate in measuring plant water needs. Such devices and methods are often problematic due to the location and number of sensors necessary to obtain accurate soil moisture readings, the high costs of installing and maintaining the sensors, and the integrity and reliability of the sensors' data. Nevertheless, soil moisture sensing devices and some simplified aspects of ET can be used in some embodiments of the present invention.
For about twenty years, most irrigation controllers have had a feature called the “seasonal adjust” feature. Typically the controller is programmed with the irrigation schedule and station run times appropriate to its installation time of the year and suitable for the type of landscape vegetation and soil type. As the seasons change or it gets cooler or warmer, the seasonal adjust feature allows the user to manually change the baseline station run times set at the time of initial installation. This is a convenience feature that allows for the changing of all station run times on the controller or stations assigned on a particular program at one time. While this feature has been commonly available, the homeowners or landscape maintenance personnel only use this feature an average of 3 times a year. In between each adjustment is where most of the landscape water is wasted. Smart watering methods and apparatus are needed to automate features such as this to be more effective for water conservation.
There are two primary ways to incorporate smart water technology using irrigation controllers. The first is to have it designed directly into the controller with software and features which require input from environmental sensors such as temperature, wind, relative humidity, or solar radiation or combinations thereof. The alternative is to have an add-on or a plug-in that is attached to the controller to adjust its irrigation schedule or watering durations. While add-ons and plug-ins are both generally separate from an existing controller, a distinction is made between the two. An add-on works with any brand of controller, normally installed in series on a common line to the valves, and may, for example, break the common line (shutting off the valves) under certain conditions. Many simple rain switches and soil moisture sensors are add-ons because they are installed on and break the common line, and when excessive precipitation or ground moisture is detected. A plug-in, on the other hand, literally plugs into only certain brands or models of controllers, and therefore requires compatibility with the controller. The Hunter Solar Sync and ET system and the Irritrol Climate Logic are examples of plug-ins, along with more sophisticated rain switches, moisture sensors, and weather stations.
ET, or evapotranspiration, is the theoretical calculation of the amount of water needed by plants to replace water lost through plant absorption and evaporation, and is expressed in inches or millimeters of water per day. The United States Food and Agriculture Office (USFAO), in its Irrigation and Drainage Paper No. 24, entitled “Crop Water Requirements,” noted that “a large number of more or less empirical methods have been developed over the last fifty years by numerous scientists and specialists worldwide to estimate ET from different climatic variables.”
There are at least 15 different ET formulas. Each of these formulas provides a different result for the reference ET (ETo). In their paper entitled “Methods to Calculate Evapotranspiration: Differences and Choices,” Diego Cattaneo and Luke Upham published a four-year comparison of four different ETo formulas—the Penman-Monteith formula, the Schwab formula, the Penman formula, and the Penman program. Using the same four year data but different weather parameters and ET algorithms, the four theoretical ET calculations show results that vary by as much as seventy-percent (See FIG. 8) during certain times of the year.
Irrespective of these variations, a modified version of the Penman-Monteith formula (which varies the most from the other three equations) is still recognized as the “standard” by both the USFAO and California Irrigation Management Information System (CIMIS). Variances of less than twenty percent from this ET are considered acceptable, particularly as an irrigation deficit. In its first draft specification the EPA dated December 2009, the EPA proposed that up to a 20% deficit was not only acceptable, but in many cases was desirable during SWAT testing for the purposes of WaterSense labeling. It is now generally accepted that the Pennman-Monteith calculation provides 20% more irrigation than required. The Penman-Monteith formula is as follows:
  ETo  =                    Δ        ⁡                  (                      Rn            -            G                    )                            λ        [                  Δ          +                      Y            ⁡                          (                              1                +                                  CdU                  ⁢                                                                          ⁢                  2                                            )                                            +                  y        ⁢                  37                      Ta            +            273.16                          ⁢        U        ⁢                                  ⁢        2        ⁢                  (                      Es            -            Ea                    )                            Δ        +                  Y          ⁡                      (                          1              +                              CdU                ⁢                                                                  ⁢                2                                      )                              
The variables within this formula represent the following:                ETo=grass reference evapotranspiration in millimeters per day.        Δ=slope of saturation vapor pressure curve kPa° C. at the mean air temperature.        Rn=net radiation (MJm−2h−1).        G=soil heat flux density (MJm−2h−1).        Y=psychometric constant (kPa° C.).        Ta=mean hourly air temperature (° C.).        U2=wind speed at two meters (m s−1).        Es=saturation vapor pressure (kPa) at the mean hourly air temperature        Ea=actual vapor pressure (kPa) at the mean hourly air temperature in ° C.        λ=latent heat of vaporization (MJkg−1).        Cd=bulk surface resistance and aerodynamics resistance coefficient.        
The simplest ET formula is the Hargreaves formula proposed by the College of Tropical Agriculture and Human Resources at the University of Hawaii at Manoa. Its equation is described in the College's Fact Sheet Engineer's Notebook No. 106, published May 1997, in an article entitled “[a] Simple Evapotranspiration Model for Hawaii,” as follows:ETo=0.0135(T+17.18)Rs 
The variables within this formula represent the following:                ETo=potential daily evapotranspiration in mm/day.        T=mean daily temperature (° C.).        Rs=incident solar radiation converted to millimeters of water per day (MJ).        
This formula relies upon the same ET theories and interrelationships as the other formulas disclosed above. As described herein, such reliance causes the Hargreaves formula to possess the same shortcomings as the other ET formulas.
In view of the significant discrepancies between various ET equations, as noted, the question is, which, if any, of these equations is the most accurate ET, or are they all merely theoretical estimations? The inventions described herein are not so much theoretical as practical and user-friendly alternative approaches to water conservation with greater potential to save real rather than theoretical water.
In an October 2005 Assembly bill 2717 task force meeting in Sacramento, Calif., the state Department of Water Resources (DWR) was asked for their definition of “Smart” controllers. The DWR described “Smart” in the same manner as the Irrigation Association, the Center for Irrigation Technology, and the EPA, in that a smart controller is capable of adjusting itself daily based upon the time of the year and the current environmental conditions and that smart technology is not limited to ET controllers.
A number of irrigation controller manufacturers currently offer ET based controllers as noted in the Bureau of Water Reclamation report. Several of them obtain the environmental data to calculate ET from historical records, while others utilize adjacently located weather stations to obtain real-time data. Others receive such information from a network of existing weather stations by radio, satellite or pager means for a monthly fee. The Irrigation Association announced at their November 2005 conference SWAT meeting in Phoenix, Ariz. that the Center for Irrigation Technology (CIT) is continuing to test all climatologically based water saving systems to include ET, ground moisture sensing, and other types of smart technology. As of October 2010, CIT is still conducting SWAT testing on climate based controllers, add-ons, and plug-ins. The EPA is in the process of establishing additional testing laboratories who will use the SWAT test protocol as the basis for their evaluation of smart controllers, rain switches, soil moisture sensors, add-ons and plug-ins, in addition to other water saving devices. Just recently, at the Smart Water Conference meeting with the EPA, it was announced that the EPA standards are proposed to be incorporated with the International Code Council standards.
The following U.S. patents all disclose various methods by which an irrigation controller calculates or adjusts an irrigation schedule based upon historical, distal, or local ETo: U.S. Pat. Nos. 4,962,522; 5,097,861; 5,208,855; 5,479,339; 5,696,671; 6,298,285 and 6,314,340. All of these methods calculate ETo values or receive them from external sources, and use such values to adjust and regulate irrigation. Such external sources may be CIMIS ET databases, local sensors, cable lines or broadcast stations. Several of these methods also utilize other data, such as precipitation.
While the replacement of the water in the vegetation root zone by means of theoretically calculated ET has been of academic interest for over fifty years, methods incorporating ET formulas, and the installation, comprehension and programming of controllers utilizing such methods, including those cited in the referenced patents above, are generally far too complex for the average user to understand and implement. Such a conclusion was reached in an earlier study of ET controllers by the Irvine Ranch Water District, entitled “Residential Weather Based Irrigation Scheduling Study.” The study stated the following: “The water agency solution to date has been to conduct residential audits, leaving the homeowner with a suggested watering schedule, hoping it would then be followed. These programs have had limited effect and a short-term impact. A preferred solution would be to install irrigation controllers that automatically adjust watering times based on local weather conditions. Unfortunately, until now, these large landscape control systems have been far too complex and expensive for residential applications.”
Such complexity is underscored by the one hundred forty-five principal symbols and acronyms identified by the USFAO for use and description of the factors and variables related to ET theory and its various formulas, covering such variables as: the capillary rise; the resistance correction factor; the soil heat capacity; the psychrometer coefficient; and the bulk stomatal resistance of a well-illuminated leaf. The sheer number of variables renders ET theory difficult to explain, understand and apply, especially for an unsophisticated consumer with little or no scientific or meteorological background. For example, the manual for one ET-based controller currently on the market comprises over one hundred fifty pages of instructions and explanations. Such unfamiliarity and complexity increase the margins of error already associated with the various ET formulas, further diminishing their effectiveness.
Water districts, irrigation consultants, manufacturers, the Irrigation Association, the Center for Irrigation Technology and other attendees at the EPA's Water Efficient Product Market Enhancement Program estimated that, due to the complexity, cost, impracticality of installation and difficulty in programming current irrigation controllers, less than one percent of all commercial and residential landscape irrigation systems currently and effectively utilize some form of the ET or moisture sensing method. While manufacturers, water districts, and irrigation consultants have accepted the concept of smart controllers as a means of landscape water conservation, homeowners (the users) have still not embraced this technology after seven years of education and encouragement with rebates.
To further emphasize this lack of acceptance, after six years of public education and encouragement with rebates and water rate increases, the Los Angeles Metropolitan Water District (that serves 3.5 million households) recently reported a total conversion of 90,000 systems to ET based controllers either provided free of charge or heavily rebated (2.6%). In another large water district, the Southern Nevada Water Authority that serves Clark County, Nevada reported in 2009 that after a three year period of 50% rebates, fewer than 100 such “smart” based controllers have been rebated. Such paltry adoption exists despite over fifty years of ET research, and over thirty years of ground moisture sensing technology. In 2006, about 1.2 million new conventional (non smart) controllers were installed or replaced in the U.S. Since the recession, this number has declined to about 700,000 controllers a year. The EPA has estimated that there currently are 13.5 million existing non smart controllers in residential use. In view of the extremely slow conversion to new ET based controllers, it would be far more effective in terms of real water conservation versus theoretical water conservation to address the 13.5 million existing controllers to make them more water efficient. Even if the ET or ground moisture sensing methods provided one hundred percent efficiency, which they do not, the limited adoption of these methods renders them an ineffective means of significant water conservation, since less than one percent of the water waste would be prevented.
A second shortcoming of the ET method is its dependence upon numerous categories of local, real-time meteorological data. As indicated above, many variables must be measured in order to calculate ET. Data for each variable must be obtained by separate sensors, each one installed in a particular location. Such particularity requires an understanding of local environmental conditions and meteorology. Furthermore, accuracy requires that the data be received from local sensors. Given the numerous microclimates existing within any one geographical area, data received from remotely located sensors may be inaccurate. The data must also be received and processed in real-time, since average or historical ET data may be inaccurate during periods of unusual or excessive heat, cold, or rain, or other deviations from historical climate patterns. Any inaccurate data would result in even greater ET deviations and inefficient irrigation. However, general trends may still be identified, even with inaccurate ET data. These general trends may be used to create the bell curves (or portions thereof) utilized in embodiments of the present invention.
ET measuring devices are generally also expensive to install and maintain. Sensors or weather stations must be placed within each microclimate to measure the different variables utilized by the formula of choice. Each weather station may cost up to several thousand dollars. Furthermore, all of these sensors or stations must undergo regular inspection, maintenance and calibration to insure that they continue to provide accurate data. This further increases the actual cost of each station. The sensors and stations must also be powered in some manner—depending upon the particular geographic location, AC power may not be readily available. All of these considerations increase the cost of implementing an ET-based irrigation system to a prohibitive level, and limit the widespread adoption of this method. Finally, all of this assumes that the weather station or sensors is even installable in a particular area. Some areas, such as street medians or parks, are not suitable for weather station or sensor installation due to aesthetic reasons or the likelihood of vandalism.
Another shortcoming of ET-based controllers is that all of the ETo formulas (including the Hargreaves formula) are generally expressed in hundredths of an inch, or millimeters, of water per day. Thus, ETo must be converted to an actual irrigation time of minutes. Such a conversion is dependent upon the characteristics of the particular hydraulic system, such as the valve sizes, water flow rates, and sprinkler or drip irrigation precipitation rates. One conversion formula, proposed by the Austin (Texas) Lawn Sprinkler Association, calculates the sprinkler run time in minutes (T) as follows:
  T  =            60      ×      ETo      ×      Kc              Pr      ×      Ea      
The variables within this equation represent the following:                ETo=reference evapotranspiration rate, in inches.        Kc=the percentage crop coefficient.        Pr=the sprinkler precipitation rate, in inches per hour.        Ea=the percentage application efficiency of the hydraulics system.        
As an example of such complexity, the crop coefficient (Kc) is different for each crop or landscape plant or grass type. Determining the precipitation rate (Pr) requires knowledge of the hydraulic system specifications—the particular types of valves and sprinklers, the number of valves and sprinklers within the system, the water flow rate and operating pressure and an actual measurement of each type of water delivery sprinkler, bubbler, or dripper. Such information is not readily available to the average consumer. Instead, the consumer must expend additional time and money to retain an irrigation expert to configure and install the system.
Another ET-to-irrigation-time conversion method, the ‘deficit irrigation practice,’ was proposed by the IA Water Management Committee in Appendix G of its October 2002 article entitled “Turf and Landscape Irrigation Best Management Practices.” This conversion method comprised ten separate formulas, and utilized a total of twenty-nine variables and constants, not including those utilized in calculating the ET value. Many of these variables represented concepts and relationships difficult for the average irrigation designer, much less a consumer, to understand, such as: the local landscape coefficient for the particular vegetation; available water depending upon the particular soil composition; allowable water depletion rate from the root zone; maximum percentage allowable depletion without plant stress; the water management factor necessary to overcome water management inefficiency; the whole day stress-based irrigation interval; water flow rates for the particular system; and, of course, ET.
Due to the urgency arising from severe national drought and environmental conditions, and the shortcomings of the various present technologies, the irrigation industry is still researching alternative methods for water conservation and prevention of unintended runoff. The Center for Irrigation Technology in Fresno, Calif., recently renamed as the Irrigation Center for Water Technology (ICWT) along with other educational and research institutions and water conservation agencies, is conducting studies evaluating various water conservation methods. On the national level, the EPA has introduced its “WaterSense” irrigation efficiency rating program similar to the “EnergyStar” rating system currently in use for equipment energy efficiency. The purpose of such an irrigation efficiency rating program is to promote consumer awareness, compliance, and standardization as an alternative to nationally and regionally mandated water conservation measures which would severely and negatively impact the irrigation industry, landscape aesthetics and the ecology. As a result, the EPA WaterSense program introduced its first draft specification for irrigation controller labeling in December of 2009. The second draft is expected in December 2010.
It is clear from the foregoing discussion that since 2003 the irrigation water management industry, in view of a politically and economically sensitive, and urgent, water crisis, is still pursuing highly scientific, mathematical and/or theoretical approaches for resolving the problems of wasted irrigation water and drought conditions. Unsurprisingly, such approaches have met with limited success. The EPA, United States Department of Energy (DOE), Bureau of Reclamation, ecologists, environmentalists, municipalities, water agencies, research institutions, irrigation consultants, and manufacturers, and now the International Code Council are all still searching for new methods that provide practical (as opposed to theoretical) improved irrigation efficiency—methods that overcome the particular shortcomings of existing systems.
California Bill 1881 states the following in Article 10.8, section 25401.9(c) under “Water Conservation in Landscaping” as follows: “On and after Jan. 1, 2012, an irrigation controller or moisture sensor for landscape irrigation uses may not be sold or installed in the state unless the controller or sensor meets the performance standards and labeling requirements established pursuant to this section.” No such standards are available to date, nor is there any projected date since the California Energy Commission has suspended its mission after three public meetings and input from irrigation professionals, manufacturers, water districts, and irrigation consultants. Therefore, the implementation of 1881 will most likely be delayed and standards not published in the near future due to the suspension of the California Energy Commission meetings due to disagreements within the industry and fiscal reasons. It is believed that several embodiments of the present invention will meet the anticipated performance standards and would therefore qualify for sale in California.
Landscape water conservation, when it is substantial and effective, also provides additional benefits. As noted by the EPA in its “Water Efficient Landscaping” guidelines, landscape water conservation also results in “decreased energy use (and air pollution associated with its generation) because less pumping and treatment of water is required and reduced runoff of storm water and irrigation water that carries top soils, fertilizers, and pesticides into lakes, rivers, and streams, fewer yard trimmings, reduced landscaping labor and maintenance costs, and extended life for water resources infrastructures (e.g. reservoirs, treatment plants, groundwater aquifers), thus reduced taxpayer costs.” Thus, there is an urgent need for irrigation systems that conserve water and energy, and minimize negative impact upon the environment, by automatically adjusting their schedules periodically in response to meteorological and seasonal changes.
The problem of irrigation mismanagement, and the main hurdle faced by these entities, can be simply summarized as follows: once a system is properly designed and installed, most of the wasted landscape irrigation water and runoff is caused by not adjusting for daily, periodic, or seasonal changes. For example, in California, most homeowners and municipalities continue to irrigate their system in the fall based upon the summer schedule until the first rain storm of the year occurs followed by a sharp drop in temperature. If the summer schedule is assumed to be 100%, and November irrigation actually only requires, for example, about 20% of summer irrigation to satisfy the vegetation needs, this means that as much as 80% of the water is wasted in the fall. Such inaction is usually caused by the complexity and difficulty of determining the particular adjustment amounts and the significant inconvenience of daily adjustments.
As an alternative to costly and impractical to install weather stations, some manufacturers are offering an ET service that broadcasts the daily ET signal by means of a satellite or pager system. An example of this approach is the AccuWater system which takes weather data collected through a private network of weather stations and or sensors. Another example is the HydroPoint Weather TRAK that requires every controller to have a receiver that either receives ET that affects the controller irrigation programming, or one that receives separate weather sensor data that is then calculated locally into an ET value (such as provided by Irrisoft with its Weather Reach Receiver and the RainBird ET Manager).
As discussed in provisional patent applications 60/831,904 and 60/899,200 (which have been incorporated above), many communities also have water pumping and delivery issues due to drought and increasing population and demand on the infrastructure delivering that water. Many of those communities have enacted limitations on watering schedules in order to minimize the demand on those facilities. The most common water restriction method has been to limit watering to odd and even days of the month, meaning that odd numbered addresses can water on the odd day of the month, while even numbered addresses can water on even days of the month. During certain times of the year, the homeowner must also manually change the allowed time of the day that he can water. By limiting landscape irrigation to certain times of the day and by either even or street address designations, or by watering groups such as designated by the SNWA (Southern Nevada Water Authority) as shown in FIGS. 21A and 21B. In the case of SNWA, the region is divided into six watering groups, designated as A-F. Watering is allowed every day during the summer for every group, but not between the hours of 11 AM and 7 PM to minimize evaporation and high peak demand periods. During the spring and fall, irrigation is permitted any time of day, but only three times a week depending upon the assigned watering group. In the winter, only one watering day per week is permitted. Fines are issued for multiple offenders. However, this method is difficult to police because there are 500,000 customers in Clark County, Nevada, so many users commonly violate these rules. It is inconvenient for the homeowner, for example, to remember to change the watering schedule and comply with the allowed watering times of the day at least 4 times a year, particularly if they are not familiar with the programming of the controller. The SNWA estimates that after 5 years of public education and rules “enforcement”, has resulted in 30% estimated compliance. While there is still a long way to go, this is far better in terms of saving real water and easing infrastructure demands than rebated ET based controllers or ground moisture sensors have shown to date. With ET related complexities and frequent disregard for watering time of use rules, a simple, intuitive solution would be highly preferred over the existing highly theoretical and technical, but impractical, state of the art ET-based and ground moisture sensing control systems and dependence upon human manual compliance with restricted watering schedules.
Furthermore, according to the EPA support statement of December 2009 accompanying their first draft WaterSense Specification, there are thirteen and a half million existing residential controllers in current use nationally. While ET based controllers address newly installed systems, existing non smart controllers, including battery powered controllers have not been addressed. Since it will most likely take a decade to replace all existing controllers with smart controllers, some simple inexpensive methods are needed to save water in the interim, because ET based methods and soil moisture sensors have not been effective in providing meaningful water conservation over the last decade since the use of ET was promoted within the irrigation industry and state and federal government agencies The relatively low cost of water, the ET based controller's initial high cost and complexity, and monthly service fees have contributed to the very low usage of ET based controllers, add-ons, plug ins.
It is therefore desirable to provide simple, user-intuitive and readily acceptable landscape water conservation methods and devices.
It is desirable that these methods and devices have a minimum of environmental sensor inputs, and a minimum of additional controller programming to implement smart water technology so as to not require professional installation or water audits.
It is also desirable that these methods not require monthly ET based service fees
It is also desirable that these methods and apparatus can be implemented within the controller, or through an add-on or plug-in device to address the 13.5 million existing irrigation controllers in the U.S. (according to the EPA WaterSense draft specification of December 2009).
It is also desirable that these methods and apparatus be reasonably retail priced so as to not depend upon rebates for their acceptance.
It is also desirable that automation be provided within controllers, add-ons or plug-ins for watering restrictions alone or in combination with smart controllers, plug-ins or add-ons.
It is also desirable to automate water budgeting by providing simple, user-intuitive, and readily acceptable water conservation approaches, and clearly understood automated methods and apparatus for calculating and/or implementing adjustments to irrigation schedules.
It is further desirable to provide methods and apparatus that automate the “seasonal adjust” function of irrigation controllers either internally to a controller, or using add-ons or plug-ins.
It is preferable, but not necessary, to utilize temperature budgeting, air or ground moisture sensing, or even historical ET in automating water budgeting.
It is further desirable to provide methods and apparatus that minimize the margins and sources of errors by minimizing the number of sensor inputs required by the variables in the formulas.
It is further desirable to provide methods and apparatus that utilize minimal local, real-time meteorological data that is not necessarily ET based.
It is further desirable that such methods and apparatus be cost-efficient, affordable, installable, and usable by a large number of people and entities within the irrigation industry with the widest range of applications possible.
It is further desirable that such methods and apparatus be understandable by the average consumer.
It is further desirable that such methods and apparatus be accomplished automatically, without requiring regular manual adjustments by the operator of the irrigation watering time settings or schedules.
It is also desirable that temperature budgeting be adaptable to time of use restrictions established by various communities or water agencies.
It is also highly desirable to provide very simple methods and apparatus for water conservation for existing AC and DC powered controllers for faster implementation of landscape water conservation.